Researchers have found a new way to detect tiny pieces of plastic waste in the ocean using fluorescent dye. They say the new method is less expensive but more effective at identifying invisible microplastics.

What Are Microplastics?

Plastic is the most prevalent kind of debris found in the open ocean and Great Lakes today. They come in different sizes and shapes, but those that are about the size of a sesame seed are known as microplastics.

Microplastics mainly break away from larger plastic materials and they are so small in size, most of them are lost and invisible. One study suggests that around 99 percent of plastic in the ocean remain hidden.

The New Method: Fluorescent Dye

In order to test the new technique, researchers at the University of Warwick had collected samples of tiny plastics from seawater around the coast of Plymouth in England.

They tried to apply the method to the samples they extracted and found the technique to be more effective at pinpointing microplastics than other conventional methods. They also found that the number of microplastics was much larger than they previously thought.

Gabriel Erni-Cassola, one of the authors of the study, said that this method allows scientists to view and analyze a huge series of samples much faster, and to get huge amounts of data on the number of microplastics in seawater.

Erni-Cassola added that in current methods, scientists have to pick samples of microplastics one by one in order to determine the amount.

How Fluorescent Dye Works?

Fluorescent dyes can attach to plastic particles and make them more visible under a fluorescence microscope. By using the dye, scientists were able to pinpoint microplastics from among other natural materials in the marine environment.

Most Microplastics Made Of Polypropylene

Researchers at the university have also found that the majority of microplastics were made of polypropylene, a common thermoplastic polymer that is used in packages and containers for food. This suggests the link between consumer habits and its effects on the ocean.

Dr. Joseph A. Christie-Oleza, a co-author of the study, said the method still needs to be carried out in scientific surveys in the future in order to confirm these results and also to understand how plastic waste behaves in the marine environment.

The study is called "Lost, but found with Nile red; a novel method to detect and quantify small microplastics (20 μm-1 mm) in environmental samples" and was published in the Environmental Science & Technology.